On the go mod topic...
Imagine the screen sliding up like the go on you GBC ? To reveale the extra buttons that the psp has. So you could kinda make it look like a stock GBC and slide the screen up to reveal the extra buttons that the PSP needs.
BTW PSP1000 mobo's can not video out. The best way to do this is to use the Video out instead of trying to connect a smaller screen to the PSP LCD out.
So PSP2000 and newer boards need to be used and IRshell would make this run more smoothly .